Evaporator structure for refrigerators



Feb. 4, 1958 J. B. THOMAS 2,821,845

EVAPORATOR STRUCTURE FOR REFRIGERATORS Filed 001;. 15, 1954 L 1 I. I

IN V EN TOR. JESSE. B. THOMAS m J M ATTQRNEY Fig.6

United Stat Patent EVAPORATOR STRUCTURE FOR REFRIGERATORS Jesse B. Thomas, Louisville, Ky., assignor to Reynolds Metals Company, Louisville, Ky., a corporation of Delaware Application October 15, 1954, Serial No. 462,471

3 Claims. (Cl. 62-126) 2,821,845 Fatented Feb. 4,19 5 8 The invention will be described in greater detail in the following specification taken in connection with the accompanying drawing illustrating preferred embodiments by way of example, and wherein:

Figure 1 is a plan view of a fiat evaporator plate embodying the invention;

Figure 2 is a section taken on line lIIl of Figure l;

Figure 3 is a partly diagrammatic view illustrating the method of manufacturing the evaporator shown in Figure 1;

Figure 4 is a View similar to Figure l of a modification;

Figure 5 illustrates the method of manufacture of the modification shown in Figure 4; and

Figure 6 is a fragmentary view of a further modification.

Referring to the drawing, Figure 1, thereis shown an evaporator plate in flat condition constructed according to the invention. The plate 1 may be made by roll bonding together two sheets of aluminum 1a and 1b, as shown in dotted lines in Figure 2, having a resist therebetween tube in a wall of the compartment in heat exchange relation to the effluent gas or liquid refrigerant flowing from the freezer.

Another object is the provision of a freezer compartment made by bonding together metal sheets, which provides a sheath in a wall of the compartment to receive a capillary tube.

A further object is the provision of a freezer compartment made by bonding together sheets of metal and expanding certain unbonded areas to provide passageways between the walls, with provision for expanding the capillary tube sheath at the same time.

According to the present invention I provide an improved structure by which the capillary tube is maintained in heat exchange relation to the effluent vapors or liquid from the freezer portion of the refrigerator throughout its circumference. That is, the capillary tube is embedded in the evaporator, and may be in heat exchange relation with the efiluent gas or liquid coming directly from the evaporator, or, where the freezer portion includes an accumulator as part of the freezer wall, the capillary tube may be in heat exchange relation to efiiuent gas, from the accumulator. The capillary tube may be located where it is surrounded by the effiuent gas, or it may be in heat transfer contact with a wall of the evaporator or accumulator subject to the temperature of the eflluent gas or liquid.

In making a freezer unit by suitably bonding together sheets of metal, such as aluminum, face to face to provide evaporator passages and other related chambers, it is quite difficult to maintain the accuracy required to provide an inlet passage of capillary size. Furthermore, where the evaporator is made of aluminum, it is diflicult to bond the capillary tube to the aluminum so that the ditliculties of manufacture are increased.

According to another feature of the present invention, 1 provide an enlarged efiluent or discharge passage in the evaporator connected at its inner end to both the inlet of the evaporator and the discharge end of the evaporator or accumulator, and the capillary tube passes into this passage and is connected to the evaporator inlet by an arrangement that seals off the evaporator inlet from the evaporator outlet. The above described structures provide a protective sheath for the capillary tube so that the tube is protected from damage during shipment or handling.

to define the various passages, which remains unbonded, and then pressure expanding the unbonded areas to provide an evaporator passage 2 which is in the form of a serpentine passage. The evaporator is shown as a flat plate but it will be understood this plate may be bent to I form a tunnel or box. The outlet connection for efi'luent gas from the evaporator comprises a tube 4 suitably joined, as by welding, to the evaporator plate 1 at the outlet end of the last run 5 of the evaporator passage.

Between the sheets forming the evaporator plate is provided a tubular space 6 which is disposed closely adjacent the last run 5 of the evaporator chamber. This space 6 is of such diameter as to easily receive a capillary tube 7 which passes through this space and is bent back at 8,

with its end 9 welded or otherwise secured to the inlet end of run 11 of the evaporator. After the capillary tube is inserted in tubular space 6 and the end of the capillary tube is welded to the evaporator inlet end, the tubular space 6 may be reduced by crimping to firmly contact the wall of the capillary tube in heat conducting relation' to the evaporator plate; or the space around tube 7 may be filled with a heat conducting filler compound. The space 6 thus serves as a sheath for the capillary tube, and the wall of this sheath is in heat conducting relation to the capillary tube throughout the circumference of the capillary tube. It will be seen that in this arrangement the capillary tube 7, which supplies liquid refrigerant to the inlet end of run 11 of the evaporator, is closely adjacent and in heat exchange relation to the last or discharge run 5 of the evaporator.

This evaporator may be made by a roll bonding operation. The direct product of the roll bonding operation is shown in Figure 3 in which the plate 1 is of excessive length, and the two sheets 1a and 1b are bonded together except where a resist between the sheets provides unadhered areas comprising the tubular space 6 and the evaporator chamber 2, which latter includes inlet run 11 and outlet run 5. The tubular space 6 circles around at 12 to connect with the end of run 11. Thus, by applying hydraulic pressure from the two passages 5 and 6, the evaporator chamber 2, including runs 5 and 11, and tubular space 6, are expanded in one operation. Then, the plate may be cut off as indicated at the dot and dash lines 13, 14 to leave space 6 open at both ends, and to open the end of run 11. The capillary tube 7 then is inserted in sheath 6, and it is bent around as indicated at 8 and welded to the end of run 11. The wall of sheath 6 may be crimped or compressed to engage tube 7 in heat exchange relation, or the space in sheath 6 around tube 7 may be filled with a heat conducting plastic or solder of known suitable composition.

In the modification shown in Figures 4 and 5, the evaporator chamber 2 is formed so as to have its inlet run 11 and outlet run 5 extend to opposite edges, and the evaporator chamber 2 is so formed as to have part of the outlet run 5:: closely adjacent the inlet run 11. Near the middle a section outlined in dot and dash lines is removed, after the passageway has been expanded, to provide an opening 150. The capillary tube 7 is then inserted into the part 11a of run 11 and across space 15a and the end of the capillary tube is welded to edge 16 of the cut away portion, so that the capillary tube connects with the inlet end of run 11 of the evaporator, and the portion 11a may be crimped to provide intimate contact of the capillary tube with the plate 1. The cut out portion 15a allows space in which to perform the welding operation, and it will be seen the capillary tube is closely adjacent the outlet portion 5a of the evaporator chamber and in heat conducting relation thereto.

In the modification shown in Figure 6, the evaporator passage 2 forms a closed circuit connecting at 17 to a common branch 18. The capillary tube 7 is inserted in branch 18 in spaced relation to the wall of this passage, with a sealing medium 19 located at its end. After the capillary tube and sealing medium, which may be neoprene or other suitable packing, are inserted, the passage 18 may be crimped around the packing to compress it, so that the packing separates the inlet of the evaporator from the outlet connection 17, and efiluent gas or liquid from the evaporator flows through passage 18 surrounding the capillary tube and is thus brought into intimate heat exchange relation with the liquid refrigerant being supplied to the evaporator.

The foregoing structure and method of manufacture enables a capillary tube to be connected to the evaporator inlet end sheathed in the wall of the evaporator plate so that the surface of the capillary tube around its periphery is in heat exchange relation to the evaporator at the outlet. This method is especially applicable to the manufacture of a roll bonded structure where it is not possible to produce a satisfactory passageway of capillary size between the sheets. However, by incorporating the sheathing tube for the capillary tube in the evaporator plate the sheathing tube may be expanded at the same time the evaporator is expanded and by the same pressure connection.

I claim as my invention:

1. In an evaporator: an evaporator wall providing an evaporator chamber therein having an evaporator outlet passageway within the confines of said wall, through which passageway flows effluent fluid from the evaporator; a portion of said outlet passageway forming a sheathing conduit within the confines of said wall; a socket portion connecting the inlet end of said evaporator chamber with said sheathing conduit; a capillary tube extending through said sheathing conduit and having its interior end connected in said socket in sealing relation to said outlet passageway; and the exterior diameter of said capillary tube being smaller than said sheathing conduit to provide space around the capillary tube for flow of efiluent fluid through said outlet passageway.

2. An evaporator structure comprising: a pair of metal sheets bonded together in face-to-face relation and providing between them separation spaces forming an evaporator chamber having an inlet and outlet, and a sheathing conduit forming a part of said evaporator. chamber adjacent said outlet, the conduit and the inlet being connected by a portion of said separation spaces; a capillary tube extending through said conduit and into said portion of said separation space to supply fluid to said inlet of said evaporator chamber; and means for sealing said capillary tube within said portion of the separation space to seal said inlet from said outlet, the exterior diameter of the capillary tube being smaller than said conduit to provide space around said capillary tube for flow of fluid through said conduit in heat exchanger relation to said capillary tube toward said outlet.

3. An evaporator structure as specified in claim 2 wherein: said sealing means comprises packing, and the wall of said portion of the separation space is compressed into engagement with said packing.

References Cited in the file of this patent UNITED STATES PATENTS 1,723,659 Rosenqvist Aug. 6, 1929 2,096,075 Tull et al Oct. 19, 1937 2,212,864 Karmazin Aug. 27, 1940 2,359,926 McCullough Oct. 10, 1944 2,619,811 Philipp Dec. 2, 1952 2,662,273 Long Dec. 15, 1953 2,682,158 Powell June 29, 1954 2,703,702 Meinel Mar. 8,1955 

